LibCpp: Modify Token::to_string() to include more information

Token::to_string() now includes not only the token's type, but also its
text and span in the document.

Userland/Libraries/LibCpp/Token.cpp

@@ -5,6 +5,7 @@
  */
 
 #include "Token.h"
+#include <AK/String.h>
 
 namespace Cpp {
 
@@ -24,4 +25,15 @@ bool Position::operator<=(const Position& other) const
 {
     return !(*this > other);
 }
+
+String Token::to_string() const
+{
+    return String::formatted("{}  {}:{}-{}:{} ({})", type_to_string(m_type), start().line, start().column, end().line, end().column, text());
+}
+
+String Token::type_as_string() const
+{
+    return type_to_string(m_type);
+}
+
 }